Automatic fire extinguishing system

ABSTRACT

An automatic fire extinguishing system employing water as the firefighting medium and having sprinkler heads with nozzle apertures sealed with low melting point temperature responsive elements and charged with air under pressure to maintain the sprinkler heads dry while in a ready status.

United States Patent [1'91 James 1 AUTOMATIC FIRE EXTINGUISHING SYSTEM [76] Inventor: Russell H. James, Main St., Box 25,

Volountown, Conn. 06384 [22] Filed: Dec. 14, 1971 [211 Appl. No.: 207,801

Related US. Application Data [63] Continuation of Ser. No. 82,995, Oct. 19, 1970,

abandoned.

52 us. C1. 169/37, 169/8 51 rm. Cl. A6 2c 37/08 58 Field of Search 169/37, 8,9, 16

56 References Cited 7 UNITED STATES PATENTS 3,702,159 11/1972 Livingston 169/37 Nov. 13, 1973 1,075,091 10/1913 Cooney 169/8 1,234,620 7/1917 Brodton... 169/8 3,407,879 10/1968 ORear 169/9 Primary Examiner-Lloyd L. King AttorneyJohn M. Prutzman et a1.

[57] ABSTRACT An automatic fire extinguishing system employing water as the firefighting medium and having sprinkler heads with nozzle apertures sealed with low melting point temperature responsive elements and charged with air under pressure to maintain the sprinkler heads dry while in a ready status.

6 Claims, 12 Drawing Figures PAIENIEDImv I 3 I975 SHEET 10F 3 FIG-3 PIC-1.2

FI G1 FIG-5' PIC-3.8

FIG.6 F19 PATENTED NOV 13 I975 SHEET 2 BF 3 FIG. /0

1 AUTOMATIC FIRE EXTINGUISI-IING SYSTEM The present application is a continuing application of my copending application Ser. No. 82,995 filed Oct. 19, 1970 and entitled Home Fire Protection Systems now abandoned.

BRIEF SUMMARY OF THE INVENTION The present invention relates to a new and improved automatic fire extinguishing system and a new and improved sprinkler head therefor of the type employing a low melting point temperature responsive element for automatically triggering the discharge of a firefighting medium such as water.

It is a principal aim of the present invention to provide a new and improved automatic fire extinguishing system having economical and reliable components and useful as a complete fire extinguishing'system in a home or other facility.

It is another aim of the present invention to provide a new and improved automatic fire extinguishing system in which the system components are protected against corrosion, etc., by the water or other fluid employed in the system for combating fires.

It is a further aim of the present invention to provide a new and improved automatic sprinkler head for a fire extinguishing system having a design permitting substantial flexibility in establishing the sprinkler head locations in the system.

It is another aim of thepresent invention to provide a new and improved fire extinguishing system of the type employing water as the fire combating medium and useful in unheated areas such as, in an unheated barn or home attic wherein the ambient temperature may be below freezing.

It is a further aim of the present invention to provide a new and improved automatic sprinkler head for a fire extinguishing system having an economical and compact assembly and providing complete reliability over a very long service-free life.

' showing additional sprinkler head modifications;

It is still a further aim of the present invention to provide a new and improved automatic fire extinguishing system for fighting fires with ablanket of steam.

It is another aim of the present invention to provide a new and improved automatic sprinkler head for a fire extinguishing system operable for signalling the automatic activation of the sprinkler head.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

A better understanding of the invention will be obtained from the following detailed description and the accompanying drawings of illustrative applications of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS broken away and partly in section, similar to FlGf-3,

showing sprinkler headmodifications;

FIGS. 9 and 11 are longitudinal section views, partly broken away and partly in section, of additional embodiments of a sprinkler head incorporating the present invention;

FIG. 10 is a longitudinal section 'view, partly broken away and partly in section, of a nozzle insert which may be employed in the sprinkler heads of FIGS. 9 and 11; and

FIG. '12 is a schematic view showing a home automatic fire extinguishing system incorporating an embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now'the drawings in detail wherein like parts are designated by like numerals throughout the several figures an embodiment 10 of an automatic fire extinguishing system incorporating the present invention is schematically shown in FIG. 12 installed in a home 12 for providing automatic fire protection in the home basement 14, first floor l6 and attic 18. For purposes of explanation, the system 10 is shown employing a limited number of automatic sprinkler heads 20, 22, 24 and, of course, in any specific installation, the numher and location of the sprinkler heads will depend on the size of the room and the desired sprinkler head spacing, etc. The sprinklerhead 20 is specifically designed to be mounted upright, as for example, along a wall or in the corner of a room (and substantially hidden within the wall or by suitable molding if desired). The sprinkler head 22 is specifically designed to be mounted horizontally as for example, along the edge of .a ceiling (and substantially hidden by suitable molding if desired). The sprinkler head 24 has a projecting nozzle25 and is specifically designed for being mounted within or along a ceiling with the nozzle 25 projecting downwardly into a'room.

The shown automatic fire extinguishing system 10 employs water as the firefighting medium but any other suitable fluid may be employed where desired. (As will become apparent hereinafter, the fire extinguishing system may be used'even with a corrosive firefighting medium without requiring the sprinkler heads to be constructed of special materials.) Thus, in the shown embodiment, an inlet conduit 30 of the fire extinguishing may be connected to any available water system in which the water pressure and volumetric flow are sufficient to provide an adequate supply of water to each of the sprinklerheads.

A suitable inlet valve 32, for example a gate valve, is provided in the inlet conduit 30 for disconnecting the remainder of the system, for example, for installing, bleeding or repairing the remainder of the system. An upstanding tank or plenum 34 having a volumetric capacity depending on the total volumetriccapacity of the system is provided in the system and the lower end of the tank' 34 is connected to'the inlet conduit 30. A drain valve 36 is shown provided for draining the tank and remainder of the system when desired. The upper outletend of the tank 34 is connected via an outlet conduit 38 to the various conduits leading to the automatic sprinkler heads 20, 22, 24.

"A suitable sight guage 40 is mounted in the outlet conduit 38 for determining if thereis water at that point in the outlet conduit. The sight guage 40 may, for example, be of the type having a ball or other float which is lifted into view by the water to signal the presence of water in the outlet conduit. A suitable air valve 46 is connected to the outlet conduit 38 via a shut-off valve 47 for supplying air under pressure to the system. A pressure guage 48 is connected to the system to provide a reading of the system pressure at the outlet conduit 38.

In accordance with the present invention, the volumetric capacity of the tank 34 is made sufficient to provide for pressurizing the system conduits and sprinkler heads with air when the system is connected to the available water system. For example, if the inlet water pressure were 45 psi, the air in the system would be compressed to approximately one-fourth of its original volume when the system inlet valve 32 is opened. Thus, if the total volumetric capacity of the system exclusive of the tank were 5 gallons, a tank with a tank capacity of, for example, 25 gallons would be employed to ensure that the tank is incompletely filled with water and the remainder of the system is charged with compressed air. Alternatively, the system could be pressurized in advance by connecting a suitable air pump to the air valve 46 and opening the shut-off valve 47. The system pressure could thereby be preset to eliminate the tank 34 or reduce the required tank capacity. Also, the air valve 46 could be used when needed to lower the water level in the system. Also, the tank 34, instead of being mounted in the basement 14 could be mounted at a higher level, in which event, the system air pressure would be described in accordance with the increased vertical head of water. Also, the tank 34 could be employed in conjunction with only part of the system to ensure that that part of the system is completely dry and with the remainder of the system partially wet but with the sprinkler heads positioned so that they remain dry due to the air in the conduits being compressed into the sprinkler heads. For example, a tank could be used in conjunction with just the attic portion of the system.

Maintaining the system in a ready'status with the sprinkler heads 20, 22, 24 remaining dry ensures that the sprinkler heads do not corrode, etc., during the usual many years the system would be expected to remain in a ready status. Also, that portion of the system charged with compressed air can be used in an attic, barn or other facility where the ambient temperature may be below freezing without effecting the proper operation of the system.

The system conduits are preferably located so that the system conduits and sprinkler heads may be completely drained with low point drain valves 49. Accordingly, any condensation forming within the system conduits and sprinkler heads may be readily drained from the system. Also, to reduce any condensation forming in the system and eliminate any tendency for gradual absorption of the pressurized air into the water contained in the tank 34, a suitable frangible air/water separator 56 may be provided in the tank 34. The separator 56 in effect floats on the water and provides an interface between the water and air. The tank 34 is preferably cylindrical in which event the separator 56 would be circular and preferably have a suitable peripheral annular seal 58 engaging the inner cylindrical wall of the tank and permitting air to pass upwardly by the separator 56 when the inlet valve '32 is opened. The

separator 56 has an enlarged central opening 60 and an underlying frangible cover 62 of a suitable material secured over the opening 60 by a ring 64 and such that the frangible cover 62 will automatically be punctured by the differential pressure across the cover when any sprinkler head is activated.

Various embodiments of the upright sprinkler head 20 are shown in FIGS. 1-8. Referring to FIGS. 1, 2 and 3, an embodiment 68 of an upright sprinkler head in accordance with the present invention comprises a generally cylindrical body 70 with external pipe threads at both ends, a switch cap 72 threaded onto the upper end of the body 70 and a switch operating plunger 74 mounted within a longitudinal bore 76 extending through the body 70. The sprinkler head 68 is shown connected to a tubular conduit 78 in a conventional manner by a nut 80 securely retaining a flared conical end 82 of the tube 78 in engagement with a conforming conical seat 84 at the lower end of nozzle body 70. The upper end 81 of the longitudinal bore 76 is enlarged and the plunger 74 has an enlarged head 83 with a lower connical shoulder which normally rests on a connical seat or shoulder 85 of the body 70.

The plunger has an enlarged tail 86 having a diameter less than the minimum diameter of the bore 76 to permit the plunger to be inserted through the bore 76 to its position shown. The plunger is preferably made of plastic excepting for an electrically conductive cap 88 at the top of the plunger. The cap 88 forms a conical cavity and is secured within a conforming conical cavity in the head of the plunger. The plunger 74 is thereby operative to electrically connect a pair of laterally spaced contacts 90, mounted within suitable insulators 94 in the switch cap 72. Accordingly, when the nozzle is activated to discharge water (as hereinafter explained more fully) the plunger 74 will be activated upwardly (due to the buoyancy of the plunger and the impact of the moving stream of water on the tail end face of the plunger) to close the switch 88. The tail end face of the plunger is inclined as shown to provide for biasing the plunger in one direction against the tube to avoid plunger chattering.

A small lateral orifice or nozzle 96 is provided in the body 70 for discharging water when the sprinkler head is activated. The orifice 96 is preferably dimensioned to provide a relatively fine spray of water and such that the water spray produced is effective to absorb heat and to being readily converted to steam to combat any fire. A low melting point plug 100 is mounted within the orifice 96 and the orifice 96 may be formed with threads or other irregular surface as shown in FIGS. 1, 2 and 3 to assist in retaining the plug 100 within the orifice against the bias of the system pressure. Alternatively, the nozzle orifice may be relatively smooth as shown in FIG. 6 in which event the orifice may be slightly tapered inwardly to assist in retaining the orifice plug in place. The low melting point plug 100 is preferably cast in place to provide a good seal for the orifice 96. The plug 100 has a low melting point of, for example, 157 F, such that as the plug 100 is heated to that temperature it will begin to liquify and be quickly ejected from the orifice 96 by the system pressure.

The upright sprinkler heads are preferably located so that the sprinkler head nozzle is immediately below the ceiling and the nozzle plug is therefore exposed to the room temperature at the ceiling, it being understood that the highest room temperature will normally be adjacent the ceiling because of air convection. Thus, as the temperature at the ceiling reaches approximately 157 F, the nozzle head will be activated to discharge water into the room to combat any fire causing the excessive temperature. The atomized spray or fog generated by the nozzle discharge will quickly be converted into steam (and thereby absorb a substantial amount of heat due to the heat of vaporization of the water) and provide for combating any fire by cooling and then smothering the fire with a blanket of steam. Because internal fires are best combated by smothering the fire rather than by merely deluging the fire with water only one or just a few nozzles may be employed for each room, depending on various factors including the room size.

When water is being discharged through the nozzle orifice, the plunger 74 is actuated upwardly to engage the spaced contacts 90. The plunger 74 thereby functions as a switch operator to signal that the sprinkler head has been activated. As schematically shown in FIG. 12, the nozzle heads for each room may be connected to operate a corresponding annunciator light 110 when any such nozzle head is activated. Also, an inside bell 112 or other annunciator and/or an outside bell 114 or other annunciator may be provided and operated when any sprinkler head is activated.

Referring to FIG. 4, the nozzle orifice may be plugged or sealed with a cover disc 120 that is soldered by low melting point solder to the outer nozzle face and such that the cover disc 120 is released when the solder reaches a response temperature of, for example, 157 F.

Also, as shown in FIG. 5, a modified nozzle body 122 may be provided which permits employing a separate nozzle insert 124 adapted to be screwed into an enlarged threaded opening 125 in the nozzle body. With this modified nozzle body 122, an appropriate nozzle insert may be employed at each station and the nozzle insert may be removed and replaced with a like or different nozzle insert without otherwise disassembling the sprinkler head.

FIGS. 7 and 8 show modified switch designs. In FIG. 7, a cylindrical insulator 130 is mounted within the upper enlarged bore portion 81 and an hemispherically shaped metal cap 132 is mounted on a conforming hemispherical end of the plunger to provide for making electrical contact with the contacts 90. In FIG. 8, a collar 138 having an opening receiving the contacts 136 is biased downwardly by a compression spring 137 and is actuated upwardly by an upper pointed end of the plunger for making electrical contact with the contacts 136.

An embodiment of a sprinkler head 22 incorporating the present invention is shown in FIG. 9. The principal difference beteen the sprinkler head 22 and the upright sprinkler heads previously described is that a light compression coil spring 135 is provided for maintaining the switch plunger 133 in its retracted position notwithstanding the angular position of the sprinkler head. For this reason, the inner end of the nozzle body 134 is provided with an enlarged bore portion for receiving one end of the compression coil spring 135 and the eularged tail end 139 of the plunger 133 is adapted to be threaded onto the center rod section 140 of the plunger 133 for assemblying the parts together. Consequently, where the sprinkler head 22 is mounted horizontally or even upside down the plunger is held retracted by the coil spring until the sprinkler head is activated.

The sprinkler head 22 is also shown having a nozzle insert 142 with a poured'low melting point plug 100. A similar nozzle insert 146 with a diverging nozzle opening is shown in FIG. 10. This latter nozzle insert 146 is particularly useful where the nozzle head is mounted with its nozzle pointing slightly or directly downwardly.

An embodiment of a sprinkler head 24 incorporating the present invention is shown in FIG. 11 The spinkler head 24 may be identical to the sprinkler head 22 shown in FIG. 9 excepting that the sprinkler head 24 has a depending nozzle insert 25 adapted to project downwardly into a room. The nozzle insert 25 comprises a depending tube 150 with a plugged nozzle orifice 151 at its lower end. Also, a suitable deflector 152 is shown mounted on the lower end of the depending tube 150 to provide for deflecting and spraying the water in all directions.

Suitable copper tubing or pipe may be used as the system conduit and the nozzle body, cap and nuts may be made of brass and assembled together as shown in the drawings. Copper and brass parts are preferred to provide a long service-free life and flared-tube connections of the type shown in the drawings are preferred to ensure the connections are not impaired by fire and even remain intact if they are bathed in fire.

As heretofore explained, the nozzle orifice plug remains out of contact with the water in the system and therefore its temperature responsiveness is not effected by the water temperature, the conductivity of water, or the relatively high specific heat of water. Consequently, the sprinkler head remains very sensitive to any substantial increase in the room temperature at the ceiling and so that it is quickly activated if there is any fire. In addition, the sprinkler heads have an economical construction and may be made very small and therefore readily hidden if desired. The system would nonetheless'provide for effectively combating any internal fire by cooling and smothering the fire, and would remain in a ready status for an indefinite period without any required servicing of the sprinkler heads and with only periodic checks of the water level to ensure the sprinkler heads remain dry.

As will be apparent to persons skilled in the art, various modifications, adaptations and variations of the foregoing specific disclosure can be made without departing from the teaching of the present invention.

I claim:

1. An automatic fire extinguishing system comprising an inlet conduit for connection to a water supply system for supplying water under pressure to the fire extinguishing system, a tank with an inlet connected to the inlet conduit for receiving water from the water supply system and an outlet, and a sprinkler system comprising a plurality of temperature responsive automatic sprinkler heads each comprising a discharge aperture for discharging water and a temperature responsive plug sealing the discharge aperture to maintain the sprinkler head in a standby status and operative to be ejected from the discharge aperture at a predetermined temperature for automatically activating the sprinkler head for discharging water and conduit means for connecting the automatic sprinkler heads to the tank outlet, the sprinkler system, with the sprinkler heads in a standby status, being a closed system excepting for the connection of the conduit means to the tank outlet, the

tank outlet being at the upper end of the tank such that air in the tank is forced out the tank outlet to the sprinkler system when the tank inlet is connected to the water supply system to supply water under pressure to the tank, and the volumetric capacity of the tank being related to the volumetric capacity of the sprinkler system to charge the sprinkler system with compressed air when the inlet conduit is connected to the water supply system and water is supplied under pressure to the tank.

2. An automatic fire extinguishing system according to claim l wherein the tank inlet is at the lower end of the tank below the tank outlet and further comprising separator means in the tank between the tank inlet and outlet for separating the compressed air in the sprinkler system and the supply water in the tank for reducing absorption of compressed air into the water and evaporation of water into the compressed air and operable by a pressure differential across the separator means to permit the passage of water from the tank inlet to the tank outlet when any sprinkler head is activated, the volumetric capacity of the tank being related to the volumetric capacity of the sprinkler system to completely charge the sprinkler system and a portion of the tank above the separator means with compressed air when the inlet conduit is connected to the water supply system and water is supplied under pressure to the tank.

3. An automatic fire extinguishing system according to claim 1 further comprising a sight guage in the conduit means for visually determining the presence of water in the conduit means and air valve means for supplying air under pressure to the sprinkler system to increase the compressed air charge therein.

4. A method of automatically extinguishing fires with a supply of liquid firefighting medium under pressure comprising the steps of providing a sprinkler system having a plurality of temperature responsive automatic sprinkler heads each having a discharge aperture for discharging liquid firefighting medium and a temperatureresponsive plug sealing the discharge aperture to maintain the sprinkler head in a ready status and operative to be ejected from the discharge aperture at a predetermined temperature for opening the discharge aperture for automatically activating the sprinkler head for discharging the liquid firefighting medium and conduit means connecting the sprinkler heads to a supply of a liquid firefighting medium under pressure for conveying the firefighting medium to each of the sprinkler heads, and charging each of the sprinkler heads with compressed gas to maintain the temperature responsive plugs of the sprinkler heads out of contact with the liquid firefighting medium while in a ready status under the pressure of the liquid firefighting medium.

5. A method according to claim 4 of automatically extinguishing fires wherein the charging step comprises charging substantially the entire sprinkler system with compressed gas to maintain substantially the entire sprinkler system dry while in a ready status under the pressure of the liquid firefighting medium.

6. A method according to claim 5 of automatically extinguishing fires wherein the charging step comprises providing a tank of air between the conduit means and supply of liquid firefighting medium and having a volumetric capacity related to the volumetric capacity of the sprinkler system to charge substantially the entire sprinkler system with compressed air when the tank is connected to receive the liquid firefighting medium. 

1. An automatic fire extinguishing system comprising an inlet conduit for connection to a water supply system for supplying water under pressure to the fire extinguishing system, a tank with an inlet connected to the inlet conduit for receiving water from the water supply system and an outlet, and a sprinkler system comprising a plurality of temperature responsive automatic sprinkler heads each comprising a discharge aperture for discharging water and a temperature responsive plug sealing the discharge aperture to maintain the sprinkler head in a standby status and operative to be ejected from the discharge aperture at a predetermined temperature for automatically activating the sprinkler head for discharging water and conduit means for connecting the automatic sprinkler heads to the tank outlet, the sprinkler system, with the sprinkler heads in a standby status, being a closed system excepting for the connection of the conduit means to the tank outlet, the tank outlet being at the upper end of the tank such that air in the tank is forced out the tank outlet to the sprinkler system when the tank inlet is connected to the water supply system to supply water under pressure to the tank, and the volumetric capacity of the tank being related to the volumetric capacity of the sprinkler system to charge the sprinkler system with compressed air when the inlet conduit is connected to the water supply system and water is supplied under pressure to the tank.
 2. An automatic fire extinguishing system according to claim 1 wherein the tank inlet is at the lower end of the tank below the tank outlet and further comprising separator means in the tank between the tank inlet and outlet for separating the compressed air in the sprinkler system and the supply water in the tank for reducing absorption of compressed air into the water and evaporation of water into the compressed air and operable by a pressure differential across the separator means to permit the passage of water from the tank inlet to the tank outlet when any sprinkler head is activated, the volumetric capacity of the tank being related to the volumetric capacity of the sprinkler system to completely charge the sprinkler system and a portion of the tank above the separator means with compressed air when the inlet conduit is connected to the water supply system and water is supplied under pressure to the tank.
 3. An automatic fire extinguishing system according to claim 1 further comprising a sight guage in the conduit means for visually determining the presence of water in the conduit means and air valve means for supplying air under pressure to the sprinkler system to increase the compressed air charge therein.
 4. A method of automatically extinguishing fires with a supply of liquid firefighting medium under pressure comprising the steps of providing a sprinkler system having a plurality of temperature responsive automatic sprinkler heads each having a discharge aperture for discharging water and a temperature responsive plug sealing the discharge aperture to maintain the sprinkler head in a ready status and operative to be ejected from the discharge aperture at a predetermined temperature for opening the discharge aperture for automatically activating the sprinkler head for discharging the liquid firefighting medium and conduit means connecting the sprinkler heads to a supply of a liquid firefighting medium under pressure for conveying the firefighting medium to each of the sprinkler heads, and charging each of the sprinkler heads with compressed gas to maintain the temperature responsive plugs of the sprinkler heads out of contact with the liquid firefighting medium while in a ready status under the pressure of the liquid firefighting medium.
 5. A method according to claim 4 of automatically extinguishing fires wherein the charging Step comprises charging substantially the entire sprinkler system with compressed gas to maintain substantially the entire sprinkler system dry while in a ready status under the pressure of the liquid firefighting medium.
 6. A method according to claim 5 of automatically extinguishing fires wherein the charging step comprises providing a tank of air between the conduit means and supply of liquid firefighting medium and having a volumetric capacity related to the volumetric capacity of the sprinkler system to charge substantially the entire sprinkler system with compressed air when the tank is connected to receive the liquid firefighting medium. 